Starbucks is pretty famous for having weird (and often subjectively described as bad) espresso. While people are quick to point out that this is largely because they roast at much higher temperatures than other roasters, an often overlooked aspect is the fact that they massively overextract with a too-small grind to counter for the "shortness" of their shots, using too little water. This results in a smaller 0.75 oz shot of espresso that's bitter and has a higher caffeine content.

We could sit here all day and argue over whether the espresso the mastrena machine produes counts as a real shot, but I think the nail in the coffin there is that Italian regulators do not consider Starbucks' espresso to be espresso, and the only Starbucks in the nation is a Starbucks Reserve which does not use the mastrena machine or sell any standard Starbucks products you'd get in the US.

Doppio

Also that is two shots. Doppio is Italian for double. That would average like 125-130mg caffeine, but again, Starbucks espresso is weird.

Sorry for the effort post, I just care a lot about culinary chemistry and processing, kind of an interest of mine